Recent printers have sufficient print quality, and can print, e.g., a natural image with a quality equivalent to a photograph.
The number of image sensing pixels of a digital still camera (to be referred to as a DSC hereinafter) has reached several million, and the quality of a photographed image has become comparable to that of a silver halide camera.
In this background, demands have arisen for printing by a printer an image photographed by a digital camera without the mediacy of a personal computer (to be referred to as a PC hereinafter). Several products which meet these demands are available at present.
One of such products gives a great deal of attention to the fact that the DCS utilizes a removal storage medium (there are various memory cards using a flash memory). The storage medium is removed from the DSC and set into the slot of the printer to read out and print image data.
To print all images stored in the storage medium one by one, images stored in the storage medium are sequentially read out without any condition, which does not pose any technical problem.
In practice, there are needs to select an image to be printed and another image, and/or designate the number of prints for each image.
As one solution to this, DPOF (Digital Print Order Format) is receiving a great deal of attention. DPOF will be briefly explained.
The DSC generally comprises a liquid crystal display for confirming a photographed image and displaying various menus, and is also equipped with various keys (buttons). By using the display and keys, an image to be printed is selected, and the number of prints of the image is designated. The designation contents are stored as a file in a storage medium which stores the image. When the storage medium is set in a printer, a print process is done for the image in accordance with the file which describes the designation contents.
This is an outline of DPOF. The above function can be realized as far as both of the DSC and printer support DPOF.
As described above, print request contents generated on the DSC side are a DPOF text file. DSCs are projected to have a larger number of functions and describe information other than an image to be simply printed and the number of prints. For example, DSCs may describe finer designations such as designation of the size of an image to be printed and the size of a print sheet, and designation of a layout of a plurality of images on one print sheet.
The problem which arises in this case is that setups using the DSC are performed independently of the printer. For example, print sheets in various sizes can be set in even a DPOF printer, and the sheet size may be different from that set by the DSC.
This problem occurs because print setups by the DSC are done independently of the printer, as described above.
For this reason, another measure is required. As one solution, a USB (Universal Serial Bus) which is a PC connection interface of a general DSC is used to allow the DSC and printer to directly communicate with each other.
If such environment can be constructed, the DSC can grasp the printer capacity, and print conditions can be set in consideration of the capacity (or function or state), solving the above problem. In this case, the following problems must be solved.
1. A printer connected to a DSC is not the same, and it is difficult to construct the user interface of the DSC in consideration of the printer capacity. This is because items (e.g., the size and type of available print medium, print quality, and layout) in the printer capacity are not independent and linked items are different between printers.2. In general, a DPOF file is stored in a removable medium such as a CF card. Many cameras support DPOF subsets, and whether another camera can analyze a DPOF file stored in a removable medium depends on the DPOF subset supported by the camera.
For these two reasons, a file designation method used in an interface and a file designation method in a DPOF file are not always the same though a DPOF file can be analyzed by the printer by attaching a “DPOF print” button or the like to the DSC and transmitting a DPOF file to the printer. The user is confused by print instructions with different print designation methods.
Even if the DSC is directly physically connected to the printer via the interface of the DSC, it is difficult to specify each image in the DSC by a protocol used in the interface.
As described above, the DPOF describes print instruction contents in the text format. A description which designates an image directly uses a directory name and file name under which the image file is stored.
Upon connecting the DSC and printer, the process complies with PTP (Picture Transfer Protocol). However, even if the DSC transfers to the printer a file which describes print instruction contents in the DPOF format, the printer cannot request a file described by a path name from the DSC. This is because PTP does not have a command for designating a file by a path name.
DPOF has been described, and this also applies to a description language such as a markup language including HTML or XML in which an image file is linked by a path name to constitute a window.